CN116097839A

CN116097839A - UE-initiated channel access procedure in wireless communication over shared spectrum

Info

Publication number: CN116097839A
Application number: CN202080104486.7A
Authority: CN
Inventors: 何宏; 姚春海; 叶春璇; 张大伟; 孙海童; 崔杰; O·欧泰瑞; 叶思根; 曾威; 杨维东; 唐扬; 张羽书
Original assignee: Apple Inc
Current assignee: Apple Inc
Priority date: 2020-08-05
Filing date: 2020-08-05
Publication date: 2023-05-09
Also published as: US20220322425A1; WO2022027377A1

Abstract

The present invention provides a user equipment configured to connect to a Base Station (BS) through a shared channel subject to a channel access operation. The UE receives a first configuration for a BS-initiated Fixed Frame Period (FFP) (BS-FFP) and a second configuration for a UE-initiated FFP (UE-FFP); determining that no Downlink (DL) transmission is detected during a predefined time of the BS-FFP; and determining that at least one condition associated with an Uplink (UL) transmission is satisfied. The UE performs a UE-initiated channel access operation when a Downlink (DL) transmission is not detected during the predefined time of the BS-FFP and the at least one condition is satisfied. The UE performs the UL transmission during the UE-FFP when the UE-initiated channel access operation is successful.

Description

UE-initiated channel access procedure in wireless communication over shared spectrum

Background

A User Equipment (UE) may be configured to establish a connection with a network. In one example, a UE may connect to a 5G new air interface (NR) network. When connecting to a 5G NR network, a UE may utilize capabilities associated with the network. In the 5G NR standard, NR-U involves management of unlicensed (shared) spectrum. Similar to Licensed Assisted Access (LAA) in the LTE standard, NR-U provides modifications for Carrier Aggregation (CA) functions that allow unlicensed bandwidth to be used for Secondary Component Carriers (SCCs). The NR-U may also be utilized in a stand-alone configuration, wherein a single NR cell provides unlicensed bandwidth for data transmission.

NR-U is designed to maintain fair coexistence with other incumbent technologies that use shared spectrum (such as WiFi) and to do so, some regulatory restrictions may be applied depending on the particular frequency band in which it may operate. For example, if operating in the 5GHz band, a Listen Before Talk (LBT) procedure may be required to acquire the medium before transmission occurs. LBT, such as Clear Channel Assessment (CCA), may be performed by a next generation node B (gNB) on a Downlink (DL) channel before DL transmission occurs. Currently, a UE is allowed to perform (UL) transmission only when a DL signal or channel is detected for the first time. This requirement may increase UL latency, particularly for Physical Resource Access Channels (PRACH) and some delay-sensitive service types, such as ultra-reliable low-latency communications (URLLC).

Disclosure of Invention

Some example aspects relate to a User Equipment (UE) having a transceiver and one or more processors. The transceiver is configured to connect to a Base Station (BS) over a shared channel subject to channel access operations. The one or more processors are communicatively coupled to the transceiver and configured to perform operations. These operations include: receiving a first configuration for a BS-initiated Fixed Frame Period (FFP) (BS-FFP), and receiving a second configuration for a UE-initiated FFP (UE-FFP); determining that no Downlink (DL) transmission is detected during a predefined time of the BS-FFP; determining that at least one condition associated with an Uplink (UL) transmission is satisfied; performing UE-initiated channel access operation when a Downlink (DL) transmission is not detected and at least one condition is satisfied during a predefined time of the BS-FFP; and performing UL transmission during the UE-FFP when the UE-initiated channel access operation is successful.

Other exemplary aspects relate to a baseband processor performing operations. These operations include: receiving a first configuration for a Base Station (BS) initiated Fixed Frame Period (FFP) (BS-FFP) and a second configuration for a User Equipment (UE) initiated FFP (UE-FFP); determining that no Downlink (DL) transmission is detected during a predefined time of the BS-FFP; determining that at least one condition associated with an Uplink (UL) transmission is satisfied; performing UE-initiated channel access operation when a Downlink (DL) transmission is not detected and at least one condition is satisfied during a predefined time of the BS-FFP; and performing UL transmission during the UE-FFP when the UE-initiated channel access operation is successful.

Other exemplary aspects relate to a User Equipment (UE) having a transceiver and one or more processors. The transceiver is configured to connect to a Base Station (BS) over a shared channel subject to channel access operations. The one or more processors are communicatively coupled to the transceiver and configured to perform operations. These operations include: a Fixed Frame Period (FFP) (BS-FFP) reception configuration for BS initiation; determining whether the scheduled Uplink (UL) transmission will begin within N2 symbols of the BS-FFP start; performing a UE-initiated channel access operation when an Uplink (UL) transmission is scheduled to start within N2 symbols of BS-FFP initiation; and performing UL transmission during the BS-FFP when the UE-initiated channel access operation is successful.

Drawings

Fig. 1 illustrates an exemplary network arrangement in accordance with various exemplary aspects.

Fig. 2 illustrates an exemplary UE in accordance with various exemplary aspects.

Fig. 3 illustrates an exemplary network cell in accordance with various exemplary aspects.

Fig. 4 shows a channel access procedure operational diagram for an NR-U unlicensed channel, where only the gNB is allowed to initiate frame-based equipment (FBE) Listen Before Talk (LBT) operations, such as Clear Channel Assessment (CCA).

Fig. 5 shows an Information Element (IE) of semi-static channel access configuration information (semistatics channel accessconfig) for transmission to a UE in a System Information Block (SIB).

Fig. 6 illustrates an FBE operational diagram for a UE initiated FFP in accordance with an exemplary aspect.

Fig. 7 illustrates a method of FBE operation for a UE-initiated FFP in accordance with various exemplary aspects.

Fig. 8 illustrates a conditional CCA operation initiated by a UE in accordance with an exemplary aspect.

Detailed Description

The exemplary aspects may be further understood with reference to the following description and the appended drawings, wherein like elements have the same reference numerals. The exemplary aspects describe a configuration of a User Equipment (UE), where the UE may initiate a channel access procedure under certain conditions for determining a channel state of a scheduled Uplink (UL) transmission. In some aspects, an exemplary UE may be configured with two Fixed Frame Periods (FFPs), one corresponding to a channel access procedure initiated by a new generation node B (gNB), and the other corresponding to a channel access procedure initiated by the UE. The gNB initiated channel access procedure may include a frame-based equipment (FBE) Listen Before Talk (LBT) operation followed by a gNB-FFP during which the UE may detect a Downlink (DL) transmission after the FBE succeeds at the gNB. In some aspects, when a DL transmission is not detected and certain conditions for a scheduled UL transmission are met, the UE may initiate its own channel access procedure, including an FBE that, upon success, allows the UE to perform the scheduled UL transmission. In other aspects, the UE may perform some UL transmissions when the UL transmissions are within a particular symbol of the gNB-FFP, rather than configuring the UE-FFP.

Although these exemplary aspects will be described with reference to a 5G NR network, those skilled in the art will appreciate that these exemplary aspects may be modified and/or used with any network that supports the following functions: other bandwidths outside of the designated or licensed spectrum are utilized which may be shared between Radio Access Technologies (RATs). For example, legacy networks such as LTE support CA functionality, where SCCs may be established for unlicensed bands, and some of these exemplary aspects may be used with such networks, e.g., when License Assisted Access (LAA) functionality is configured. Furthermore, the NR-U can be used as a stand-alone function for connecting to unlicensed bandwidth, independent of any CA operation. Thus, the exemplary aspects described below may be used for a CA configuration or in the absence of a CA configuration.

Network/device

Fig. 1 illustrates an exemplary network arrangement 100 in accordance with various exemplary aspects. The exemplary network arrangement 100 includes a plurality of

UEs

110, 112. Those skilled in the art will appreciate that a UE may be any type of electronic component configured to communicate via a network, for example, a component of a networked automobile, a mobile phone, a tablet computer, a smart phone, a tablet, an embedded device, a wearable device, an internet of things (IoT) device, etc. It should also be appreciated that an actual network arrangement may include any number of UEs used by any number of users. Thus, the example with two

UEs

110, 112 is provided for illustration purposes only. In some exemplary aspects described below, groups of UEs may be employed to make corresponding channel measurements.

The

UEs

110, 112 may communicate directly with one or more networks. In an example of network configuration 100, the networks with which

UEs

110, 112 may wirelessly communicate are a 5G NR radio access network (5G NR-RAN) 120, an LTE radio access network (LTE-RAN) 122, and a Wireless Local Area Network (WLAN) 124. Thus,

UEs

110, 112 may include a 5G NR chipset in communication with 5G NR-RAN 120, an LTE chipset in communication with LTE-RAN 122, and an ISM chipset in communication with WLAN 124. However,

UEs

110, 112 may also communicate with other types of networks (e.g., conventional cellular networks), and UE110 may also communicate with the networks via wired connections. Referring to exemplary aspects,

UEs

110, 112 may establish a connection with 5G NR-RAN 122 and/or LTE-RAN 120.

The 5G NR-RAN 120 and LTE-RAN 122 may be part of a cellular network that may be deployed by a cellular provider (e.g., verizon, AT & T, sprint, T-Mobile, etc.). These

networks

120, 122 may include, for example, cells or base stations (NodeB, eNodeB, heNB, eNBS, gNB, gNodeB, macro, micro, small, femto, etc.) configured to transmit and receive traffic from UEs equipped with appropriate cellular chipsets. WLAN 124 may comprise any type of wireless local area network (WiFi, hotspot, IEEE 802.11x network, etc.).

The

UEs

110, 112 may be connected to the 5G NR-RAN via at least one of a next generation node B (gNB) 120A and/or a gNB 120B. The

gnbs

120A, 120B may be configured with the necessary hardware (e.g., antenna arrays), software, and/or firmware to perform massive multiple-input multiple-output (MIMO) functions. Massive MIMO may refer to a base station configured to generate multiple beams for multiple UEs. References to the two

gnbs

120A, 120B are for illustrative purposes only. The exemplary aspects may be applied to any suitable number of gnbs. Specifically, UEs 110, 112 may connect to and exchange data with

multiple gnbs

120A, 120B simultaneously in a multi-cell CA configuration.

UEs

110, 112 may also connect to LTE-RAN 122 via either or both

enbs

122A, 122B, or to any other type of RAN, as described above. In network arrangement 100, UE110 is shown as having a connection to gNB120A, while UE 112 is shown as having a connection to gNB 120B. The connection of UE110 to gNB120A may be, for example, an NR-U connection that utilizes an unlicensed portion of the RF spectrum.

In addition to

networks

120, 122 and 124, network arrangement 100 also includes a cellular core network 130, the internet 140, an IP Multimedia Subsystem (IMS) 150, and a network services backbone 160. The cellular core network 130 (e.g., 5GC of NR) may be considered an interconnected set of components that manage the operation and traffic of the cellular network. The cellular core network 130 also manages traffic flowing between the cellular network and the internet 140.

IMS 150 may be generally described as an architecture for delivering multimedia services to UE110 using IP protocols. IMS 150 may communicate with cellular core network 130 and internet 140 to provide multimedia services to UE 110. The network services backbone 160 communicates with the internet 140 and the cellular core network 130 directly or indirectly. Network services backbone 160 may be generally described as a set of components (e.g., servers, network storage arrangements, etc.) that implement a set of services that may be used to extend the functionality of UE110 in communication with various networks.

Fig. 2 illustrates an exemplary UE110 in accordance with various exemplary aspects. UE110 will be described with reference to network arrangement 100 of fig. 1. UE110 may represent any electronic device and may include a processor 205, a memory arrangement 210, a display device 215, an input/output (I/O) device 220, a transceiver 225, and other components 230. Other components 230 may include, for example, audio input devices, audio output devices, batteries that provide a limited power source, data acquisition devices, ports for electrically connecting UE110 to other electronic devices, sensors for detecting a condition of UE110, and the like. UE110 shown in fig. 2 may also represent UE 112.

Processor 205 may be configured to execute multiple engines of UE 110. For example, the engine may include a channel access engine 235 to perform operations including initiating a channel access procedure at the UE. The channel access procedure may include an FBE followed by a UE Fixed Frame Period (FFP) that includes a Channel Occupancy Time (COT) during which the UE may perform UL transmissions, as will be described in detail below. In other aspects, channel access engine 235 may cause the processor to perform operations including initiating an FBE during a gNB-FFP and performing UL transmissions when the UL transmissions are within a particular symbol of the gNB-FFP, as will be described in detail below.

The above-described engines are merely exemplary as application programs (e.g., programs) that are executed by the processor 205. The functionality associated with the engine may also be represented as a separate integrated component of UE110 or may be a modular component coupled to UE110, e.g., an integrated circuit with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. The engine may also be embodied as an application or as separate applications. Further, in some UEs, the functionality described for processor 205 is shared between two or more processors, such as a baseband processor and an application processor. The example aspects may be implemented in any of these or other configurations of a UE.

Memory 210 may be a hardware component configured to store data related to operations performed by UE 110. The display device 215 may be a hardware component configured to display data to a user, while the I/O device 220 may be a hardware component that enables user input. The display device 215 and the I/O device 220 may be separate components or may be integrated together (such as a touch screen). The transceiver 225 may be a hardware component configured to establish a connection with the 5G-NR RAN 120, LTE RAN 122, etc. Thus, transceiver 225 may operate on a variety of different frequencies or channels (e.g., successive sets of frequencies). For example, transceiver 225 may operate on an unlicensed spectrum when, for example, an NR-U is configured.

Fig. 3 illustrates an exemplary network cell, in this example, a gNB120A, in accordance with various exemplary aspects. As described above with reference to UE110, gNB120A may represent a cell that is served as a PCell or SCell or configured independently of UE 110. The gNB120A may represent any access node of a 5G NR network through which the

UEs

110, 112 may establish connectivity and manage network operations. The gNB120A shown in FIG. 3 may also represent gNB 120B.

The gNB120A may include a processor 305, a memory arrangement 310, an input/output (I/O) device 320, a transceiver 325, and other components 330. Other components 330 may include, for example, audio input devices, audio output devices, batteries, data acquisition devices, ports for electrically connecting the gNB120A to other electronic devices, and the like.

Processor 305 may be configured to execute multiple engines of gNB120A. For example, the engines may include a channel access engine 235 for performing operations including configuring a UE-FFP for a UE during which the UE may send UL transmissions, as will be described in detail below.

The above-described engines are each merely exemplary as an application (e.g., program) that is executed by the processor 305. The functionality associated with the engine may also be represented as a separate integrated component of the gNB120A, or may be a modular component coupled to the gNB120A, such as an integrated circuit with or without firmware. For example, an integrated circuit may include input circuitry for receiving signals and processing circuitry for processing signals and other information. Further, in some gnbs, the functionality described for the processor 305 is split between multiple processors (e.g., baseband processors, application processors, etc.). The example aspects may be implemented in any of these or other configurations of the gNB.

Memory 310 may be a hardware component configured to store data related to operations performed by

UEs

110, 112. The I/O device 320 may be a hardware component or port that enables a user to interact with the gNB120A. The transceiver 325 may be a hardware component configured to exchange data with the

UEs

110, 112 and any other UEs in the system 100. The transceiver 325 may operate on a variety of different frequencies or channels (e.g., a set of consecutive frequencies). For example, when configuring NR-U functionality, transceiver 325 may operate on unlicensed bandwidth. Accordingly, the transceiver 325 may include one or more components (e.g., radio components) to enable data exchange with various networks and UEs.

Channel access procedure on shared channel

NR-U is designed to maintain fair coexistence with other incumbent technologies that use shared spectrum (such as WiFi) and to do so, some regulatory restrictions may be applied depending on the particular frequency band in which it may operate. For example, if operating in the 5GHz band, a Listen Before Talk (LBT) procedure may be used to acquire the medium before transmission occurs. For example, clear Channel Assessment (CCA) may be performed by a next generation node B (gNB) on a Downlink (DL) channel before DL transmissions to a User Equipment (UE) occur. However, rel-16 NR-U currently only supports gNB as the initiating device for CCA. Thus, a UE is allowed to perform (UL) transmission only if a DL signal or channel, such as a Physical Downlink Control Channel (PDCCH), a Synchronization Signal Block (SSB), a System Information Block (SIB) (e.g., RMSI), or a packet common (GC) PDCCH, is first detected within a Fixed Frame Period (FFP).

FFP is a time resource available to a UE sending/receiving a transmission. FFP length and start position (timing offset) are parameters provided by the network in, for example, SIB1 information. Each frame period consists of a Channel Occupation Time (COT) and an idle period at the end of the FFP, after which the FFP is repeated. During a idle period before the next FFP, the gNB may perform LBT, such as a frame-based equipment (FBE) operation, e.g., a one-shot CCA, and if the CCA is successful, perform DL signaling or data transmission at FFP initiation. If DL transmission is detected at the UE, the UE is allowed to perform UL transmission within the FFP. The size of the COT may be determined according to rules defined for the FBE. For example, the idle period may be not shorter than 5% of the FFP, and the COT may be not longer than 95% of the FFP.

Fig. 4 shows a channel access procedure operational diagram 400 for an NR-U unlicensed channel, where only the gNB is allowed to initiate frame-based equipment (FBE) listen-before-talk (LBT) operations, such as Clear Channel Assessment (CCA). Example diagram 400 includes a first FFP 402 followed by a second FFP 404. The first CCA 406 is performed by the gNB prior to the first FFP 402, the first FFP 402 having a first scheduled UL transmission 410 within its COT 408. In this example operation, the first CCA 406 may be considered to fail at the gNB. Thus, during the first COT408, the gNB is not transmitting on DL. Because the UE did not detect any DL transmissions prior to the first scheduled UL transmission 410, the UL transmission 410 is discarded. The second CCA 414 is performed by the gNB during the idle period 412 at the end of the first FFP 402 and prior to the COT416 of the second FFP 404. In this example operation, the second CCA 414 may be considered successful at the gNB. Thus, during the COT416, the gNB transmits on the DL 418, and the UE detects the DL transmission 418 before the second scheduled UL transmission 420 within the COT 416. Because the UE detects DL transmission 418 before the second scheduled UL transmission 420, the UE performs the second scheduled UL transmission 420.

As shown in example diagram 400, considering that the UE needs to wait until the second COT416 to perform UL transmission 420, the UE needs to first detect DL transmissions/signals before transmitting on the UL, which increases UL delay. This delay increase may have a particular impact on the Physical Resource Access Channel (PRACH) and some delay-sensitive service types such as ultra-reliable low-delay communications (URLLC). For example, such requirements may prevent URLLC services from operating in unlicensed bands.

UE-initiated COT for FBE operation

According to some example aspects, the UE is configured to initiate an FBE and establish a second Fixed Frame Period (FFP)/Channel Occupancy Time (COT) in which UL data, e.g., high priority data, such as URLLC communications, is transmitted when the gcb initiated FBE is unsuccessful. For example, the UE may be configured with: a first FFP and a corresponding offset configuration (hereinafter referred to as "gNB-FFP") having a gNB as an FBE originating device; and a second FFP and corresponding offset configuration (hereinafter referred to as "UE-FFP") with the UE as an FBE-initiating device. The UE-FFP may be configured to be shorter than the gNB-FFP such that one or more UE-FFPs may fall within the gNB-FFP. For example, the UE-FFP may be configured as a percentage of the gcb-FFP, for example, relative to the gcb-FFP. For example, in the 3GPP standard, the candidate percentage value X of the UE-FFP period may be fixed for the UE to be, for example, 0%, 15%,30%, 45%, 60% and 95% equivalent of the gNB-FFP period, where this indicates that the UE is not allowed to act as an FBE originating device when the value is configured to be 0. The UE-FFP may be configured by a System Information Block (SIB), e.g., configured in SIB1 (SIB common to all UEs within the same serving cell), or by dedicated RRC signaling.

Fig. 5 shows an Information Element (IE) 500 of semi-static channel access configuration information (semistatics channel accessconfig) for transmission to a UE in a System Information Block (SIB). IE 500 may be an asn.1 message prepared for separate FBE configuration parameters to enable the UE to act as an FBE originating device. In this example, IE 500 includes a first row (period) 502 for configuring gNB-FFP and offset and a second row (period 2) for configuring UE-FFP and offset. In IE 500, the second row includes parameters corresponding to each of the parameters included in the first row. However, as described above, in some aspects, the UE-FFP configuration may be indicated as a percentage "X" of the period in the first row. For example, the value of X may be a fraction or an integer. In one aspect, the candidate X value may be fixed in the specification, e.g., x= <0,15,30,45,60,95>%, where a value of "0" indicates that the UE is not allowed to initiate COT.

Immediately before the UE-FFP starts transmitting when configured to initiate FFP, during a single observation period, e.g., tsl=9 microseconds, the UE may perform an LBT operation, such as CCA. The UE may perform an LBT operation and initiate a COT if the following two conditions are met. First, the UE does not detect any DL transmission bursts from the gNB at a predetermined time interval within the gNB-FFP prior to the start of the UE-FFP. As described above, the gNB-FFP overlaps with at least a portion of one or more UE-FFPs, but may not initiate a UE CCA (during an observation period immediately preceding the UE-FFP) during a predefined time of the gNB-FFP when a DL transmission burst is desired. In some aspects, the predefined time interval includes at least symbols configured for PDCCH, SSB, and periodic CSI-RS monitoring.

Regarding the second condition, before initiating UE CCA, the UE should have at least one PUSCH (DG-PUSCH) or Configuration Grant (CG) PUSCH transmission (CG-PUSCH) dynamically granted by the DCI format within the UE-FFP. In other words, although the actual CG-PUSCH or DG-PUSCH transmission is subject to the result of the CCA, the DG-PUSCH or CG-PUSCH should be scheduled during the UE-FFP. Alternatively, some other "predefined" UL transmissions scheduled during the UE-FFP may trigger the UE CCA to initiate COT.

In some aspects, for the second condition, the DG-PUSCH and CG-PUSCH described above may be associated with a predefined channel access priority class (caps) "p". For example, only high priority data, such as data having priority class "1" or "2", may trigger the UE to initiate UE-FFP. In this case, the CAPC threshold Tp will be 2, where p+.Tp (e.g., higher priority packets) allows triggering the occurrence of UE CCA and associated UE-COT. For DG-PUSCH transmission, the cap value "p" may be indicated in the scheduling DCI corresponding to the UL transmission. For CG-PUSCH, the cap value "p" may be determined based on the 5G quality of service (QoS) identifier (5 QI) values of all QoS flows multiplexed by CG-PUSCH.

In other aspects, for the second condition, the above CG-PUSCH corresponding to the configuration grant may have a priority value set to 1 in ConfiguredGrantConfig IE, indicating that the CG-PUSCH is high priority. DG-PUSCH is PUSCH scheduled by PDCCH and may be indicated as higher priority by using a priority indicator field in the scheduling DCI. In other aspects, the above-described so-called "predefined" UL transmissions in the second condition include, for example, UL transmissions related to RACH procedures (e.g., PRACH transmissions) and higher priority Uplink Control Information (UCI) transmissions (e.g., HARQ-ACK and SR transmissions over PUCCH or PUSCH). In another aspect, SRS transmissions may also be included in "predefined" UL transmissions.

Fig. 6 illustrates an FBE operational diagram 600 for a UE initiated FFP in accordance with an exemplary aspect. The FBE in this exemplary aspect is described as Type 2A CCA for the gNB-initiated FFP and the UE-initiated FFP (gNB-FFP and UE-FFP). However, in other aspects, other LBT categories may be used, such as Type 1CCA. Diagram 600 will be described with respect to method 700 shown in fig. 7.

Fig. 7 illustrates a method 700 of FBE operation for a UE-initiated FFP in accordance with various exemplary aspects. As described above, in 705, the gNB configures the gNB-FFP and the UE-FFP for the UE. In the example of fig. 6, subject to the first condition discussed above, the gNB-FFP 602 overlaps with the plurality of UE-FFPs 604, wherein the UE does not perform CCA (prior to the UE-FFP) during a predefined time interval in which the UE may detect a DL transmission burst from the gNB. Two UL grants are configured for the UE, in particular: a first UL grant 606, DG-PUSCH scheduled in this respect by the scheduling DCI with a cap value p=4; and a second UL grant 808, in this respect, CG-PUSCH determined to have a cap value p=1 based on the 5QI value of the corresponding data stream. In this aspect, the threshold p value Tp has a value of 2. Thus, when p.ltoreq.2, UE-FFP may be allowed to occur. The first UL grant 606 is scheduled during UE-FFP604a and the second UL grant 608 is scheduled during UE-FFP604 b.

In 710, the gNB performs Type 2A CAA before the configured gNB-FFP. In the example of fig. 6, a gNB initiated CAA 610 is performed prior to the gNB-FFP 602. In this example, CAA 610 fails at the gNB, preventing the gNB from transmitting DL transmission bursts within the gNB-FFP 602. Thus, during the predefined time interval described above, the UE does not detect any DL transmission bursts.

In 715, based on not detecting a DL transmission burst during a predefined time, the UE determines whether the subsequent UE-FFP schedules DG-PUSCH or CG-PUSCH satisfying the configuration condition. In the example of fig. 6, DG-PUSCH 606 is scheduled within UE-FFP604a after the gNB CCA. However, the priority p=4 of DG-PUSCH 606 is greater than the threshold tp=2. Therefore, these conditions are not satisfied.

In 720, the UE does not perform UL transmissions during the UE-FFP when the UE determines that any DG-PUSCH or CG-PUSCH satisfying these conditions is not scheduled for a subsequent UE-FFP. In other words, in the example of fig. 6, the UE discards the scheduled DG-PUSCH transmission 606. If additional UE-FFPs are established before the end of the gNB-FFP, the method returns to 720 and the UE performs the same determination procedure for the additional UE-FFPs. In the example of fig. 6, the UE determines: within the UE-FFP604 b, CG-PUSCH 608 is scheduled. CG-PUSCH 608 has priority p=1 less than or equal to threshold tp=2. Thus, the conditions for scheduled UL transmissions 608 are satisfied.

In 725, when the UE determines that the subsequent UE-FFP schedules DG-PUSCH or CG-PUSCH satisfying these conditions, the UE performs Type 2A CCA before the subsequent UE-FFP. In the example of fig. 6, UE-initiated CAA 612 is performed prior to UE-FFP604 b. In this example, CAA 612 was successful at the UE, allowing the UE to access the channel for the UL.

In 730, after the CCA is successful, the UE performs a UL transmission scheduled for a subsequent UE-FFP. In the example of fig. 6, the UE performs CG-PUSCH transmission 608 based on successful CAA 612 (which only allows this to occur if UL transmission conditions for the UE-FFP are met).

According to some example aspects, for a UE-FFP, the UE may perform a Type 1 channel access procedure instead of a Type 2A channel access procedure. If the Type 1 operation is configured and the above two conditions are satisfied, the UE may perform the Type 1FBE operation. Those skilled in the art will appreciate that the general characteristics of the Type 2A channel access procedure are: upon sensing that the channel is idle, the device (e.g., UE) will transmit. On the other hand, the Type 1 channel access procedure may cause the UE to sense that multiple slots are idle. Thus, in an exemplary aspect related to Type 1CCA, the UE may maintain a contention window value CWp and adjust for transmissions corresponding to each channel access priority class (caps) 'p', e.g., the number of idle slots to be sensed may depend on the caps.

According to other exemplary aspects, the energy detection threshold xthresh UE for CCA may be configured by the higher layers alone. Those skilled in the art will appreciate that the energy detection threshold is the minimum energy required to declare a channel busy during CCA. Based on associated PUSCH transmission parameters, e.g., priority class and/or 5QI value (delay requirement), the UE may autonomously select one of a set of energy detection thresholds. For example, for higher priority classes, the UE may set the energy detection threshold to a higher value to attempt transmission even though the channel may be occupied. In some aspects, the set of energy detection thresholds may be derived based on a base threshold and a number of offset values relative to the base threshold. The offset value may be determined based at least on the corresponding caps value.

In other exemplary aspects, the UE may share UE-initiated COT with the gNB. Thus, the gNB may reserve resources if it knows when the UE (if any) will initiate the UL transmission. The UE may implicitly or explicitly inform the gNB of the sharing. In a first option, detection of PUSCH transmission (e.g., DG-PUSCH or CG-PUSCH) for a UE is used as an implicit indicator of UE-FFP corresponding to the gNB sharing. In a second option, 1 bit may be encoded into Uplink Control Information (UCI) to indicate whether UE-FFP may be shared with the gNB. This provides the following flexibility: as described above, different energy thresholds are selected for CCA operation; the UE-FFP sharing is then indicated accordingly. In a third option, the UE provides a row index of a table configured by higher layers, e.g. RRC signaling, where the following are jointly encoded: the number of slots for sharing, an offset value indicating the start of UL transmission, and a cap for UL transmission. A row may indicate that there is no COT shared with the gNB.

Conditional CCA for PUSCH transmission in FBE operation

In some example aspects, the UE may additionally perform CCA for a given UL transmission (e.g., DG-PUSCH or CG-PUSCH) if the UL transmission is aligned with the gNB-FFP boundary, or if the gap between the gNB-FFP start and the PUSCH symbol start is less than N2 symbols. If these conditions are met, the UE may transmit PUSCH immediately after sensing channel idle for at least a sensing time slot duration tsi=9 microseconds. This configuration is based on a minimum scheduling delay of N2 symbols between PDCCH and PUSCH, making it impossible to schedule PUSCH transmissions over PDCCH within the same gNB-FFP.

Fig. 8 illustrates a conditional CCA operation diagram 800 initiated by the UE in accordance with an exemplary aspect. As described above, the conditional CCA operation depends on the presence or absence of CG-PUSCH or DG-PUSCH with at least one symbol within a timing window starting at the beginning of one gNB-FFP and having a duration of N2 symbols. Referring to fig. 8, gNB-FFP 802 includes PDCCH transmission 806 and gNB-FFP 804 includes PUSCH transmission 810. When the first symbol of PUSCH 604 falls within the N2 symbol time window starting at the beginning of the gNB-FFP 804, the UE performs a Type 2A CCA operation 808 to sense the availability of the channel immediately prior to PUSCH transmission 810.

In other exemplary aspects, if the UE does not detect any DL signal/channel within the gNB-FFP ending N1 symbols before the UL transmission begins, the UE does not perform CCA for the UL transmission, where N1 is the PDSCH-to-HARQ-ACK timeline capability of the UE.

Those of skill in the art will appreciate that the above-described exemplary aspects may be implemented in any suitable software configuration or hardware configuration, or combination thereof. Exemplary hardware platforms for implementing the exemplary aspects may include, for example, intel x 86-based platforms having a compatible operating system, windows OS, mac platform and MAC OS, mobile devices having operating systems such as iOS, android, etc. In other examples, the exemplary aspects of the methods described above may be embodied as a program comprising lines of code stored on a non-transitory computer readable storage medium, which when compiled, may be executed on a processor or microprocessor.

Although this patent application describes various combinations of various aspects each having different features, one skilled in the art will appreciate that any feature of one aspect may be combined with features of other aspects in any manner not disclosed in the negative or functionally or logically inconsistent with the operation of the apparatus of the disclosed aspects of the invention or the described functionality.

It is well known that the use of personally identifiable information should follow privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining user privacy. In particular, personally identifiable information data should be managed and processed to minimize the risk of inadvertent or unauthorized access or use, and the nature of authorized use should be specified to the user.

It will be apparent to those skilled in the art that various modifications can be made to the present disclosure without departing from the spirit or scope of the disclosure. Accordingly, the present disclosure is intended to cover modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.

Claims

1. A User Equipment (UE), comprising:

a transceiver configured to connect to a Base Station (BS) through a shared channel subject to a channel access operation; and

one or more processors communicatively coupled to the transceiver and configured to perform operations comprising:

receiving a first configuration for a BS-initiated Fixed Frame Period (FFP) (BS-FFP), and receiving a second configuration for a UE-initiated FFP (UE-FFP);

determining that no Downlink (DL) transmission is detected during a predefined time of the BS-FFP;

determining that at least one condition associated with an Uplink (UL) transmission is satisfied;

performing a UE-initiated channel access operation when a Downlink (DL) transmission is not detected and the at least one condition is satisfied during the predefined time of the BS-FFP; and

the UL transmission is performed during the UE-FFP when the UE-initiated channel access operation is successful.

2. The UE of claim 1, wherein the predefined time for the BS-FFP comprises a time immediately before the UE-FFP starts.

3. The UE of claim 2, wherein the predefined time for which the UE does not detect the BS-FFP for the DL transmission comprises: symbols configured for a Physical Downlink Control Channel (PDCCH), a Synchronization Signal Block (SSB), and a periodic channel state indicator reference signal (CSI-RS).

4. The UE of claim 1, wherein the at least one condition comprises one of the following being scheduled for the UE-FFP: a Physical Uplink Shared Channel (PUSCH) (DG-PUSCH) for Downlink Control Information (DCI) grant or a configuration grant PUSCH (CG-PUSCH).

5. The UE of claim 4, wherein the at least one condition further comprises: the DG-PUSCH or the CG-PUSCH is associated with a priority value that satisfies a configured priority value threshold.

6. The UE of claim 5, wherein the priority value is a channel access priority class (cap).

7. The UE of claim 6, wherein the CAPC is indicated for the DG-PUSCH in scheduling DCI or is indicated for the CG-PUSCH based on a 5G QoS identifier (5 QI) value of a quality of service (QoS) flow multiplexed in the CG-PUSCH.

8. The UE of claim 1, wherein the at least one condition includes that the UL transmission is related to one of: a Random Access Channel (RACH), high priority Uplink Control Information (UCI), or Sounding Reference Signal (SRS) transmission.

9. The UE of claim 1, wherein the UE-initiated channel access operation is performed prior to the UE-FFP, and wherein the UE-initiated channel access operation is a Type 2A Clear Channel Assessment (CCA).

10. The UE of claim 1, wherein the UE-initiated channel access operation is a Type 1 Clear Channel Assessment (CCA), and wherein at least one parameter of the Type 1CCA is based on a Channel Access Priority Class (CAPC) of the UL transmission.

11. The UE of claim 1, wherein an energy detection threshold for the UE to use for the channel access procedure to initiate the UE-FFP is configured by a higher layer and is based at least on parameters of the UL transmission.

12. The UE of claim 1, wherein the UE shares a Channel Occupancy Time (COT) of the UE-FFP with the BS, the operations further comprising:

transmitting Uplink Control Information (UCI) to the BS, the UCI including an indication of whether the UE-FFP is to be shared with the BS; or alternatively

A row index to the BS transmission table, wherein the row index indicates a number of slots for sharing, an offset at which the UL transmission starts, and a priority of the UL transmission.

13. A baseband processor configured to perform operations comprising:

receiving a first configuration for a Base Station (BS) initiated Fixed Frame Period (FFP) (BS-FFP) and a second configuration for a User Equipment (UE) initiated FFP (UE-FFP);

14. The baseband processor of claim 13, wherein the predefined time for the BS-FFP comprises a time immediately before the UE-FFP starts, and wherein the predefined time comprises: symbols configured for a Physical Downlink Control Channel (PDCCH), a Synchronization Signal Block (SSB), and a periodic channel state indicator reference signal (CSI-RS).

15. The baseband processor of claim 13, wherein the at least one condition comprises one of a Physical Uplink Shared Channel (PUSCH) (DG-PUSCH) or a configuration grant PUSCH (CG-PUSCH) for which Downlink Control Information (DCI) grants are scheduled for the UE-FFP, and the DG-PUSCH or the CG-PUSCH is associated with a priority value that satisfies a configured priority value threshold.

16. The baseband processor of claim 15, wherein the priority value is a Channel Access Priority Class (CAPC), and wherein the CAPC is indicated for the DG-PUSCH in scheduling DCI or the CAPC is indicated for the CG-PUSCH based on a 5G QoS identifier (5 QI) value of a quality of service (QoS) flow multiplexed in the CG-PUSCH.

17. The baseband processor of claim 13, wherein the at least one condition comprises that the UL transmission is related to one of: a Random Access Channel (RACH), high priority Uplink Control Information (UCI), or Sounding Reference Signal (SRS) transmission.

18. The baseband processor of claim 13, wherein the UE-initiated channel access operation is performed prior to the UE-FFP, and wherein the UE-initiated channel access operation is a Type 2A Clear Channel Assessment (CCA).

19. The baseband processor of claim 13, wherein the UE-initiated channel access operation is a Type 1 Clear Channel Assessment (CCA), and wherein at least one parameter of the Type 1CCA is based on a Channel Access Priority Class (CAPC) of the UL transmission.

20. The baseband processor of claim 13, wherein an energy detection threshold for the UE for the channel access procedure to initiate the UE-FFP is configured by a higher layer and is based at least on parameters of the UL transmission.

21. The baseband processor of claim 13, wherein the UE shares a Channel Occupation Time (COT) of the UE-FFP with the BS, the operations further comprising:

22. A User Equipment (UE), comprising:

a Fixed Frame Period (FFP) (BS-FFP) reception configuration for BS initiation;

determining whether a scheduled Uplink (UL) transmission will begin within N2 symbols of the BS-FFP start;

performing a UE-initiated channel access operation when the Uplink (UL) transmission is scheduled to start within N2 symbols of the BS-FFP start; and

the UL transmission is performed during the BS-FFP when the UE-initiated channel access operation is successful.

23. The UE of claim 22, wherein the scheduled UL transmission is one of: a Physical Uplink Shared Channel (PUSCH) (DG-PUSCH) for Downlink Control Information (DCI) grant or a configuration grant PUSCH (CG-PUSCH).

24. The UE of claim 23 wherein the one of the DG-PUSCH or CG-PUSCH is scheduled by the BS within a BS-FFP preceding the BS-FFP.

25. The UE of claim 22, wherein the operations further comprise:

within the BS-FFP, detecting a Downlink (DL) signal ending N1 symbols before the scheduled UL transmission starts, where N1 is the Physical Downlink Shared Channel (PDSCH) to HARQ-ACK timeline capability of the UE, and

wherein performing the UE-initiated channel access operation is further based on detecting the DL signal.